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Cyclin‐d1 ‐gene amplification and expression in breast carcinoma: Relation with clinicopathologic characteristics and with retinoblastoma gene product, p53 and p21 waf1 immunohistochemical expression
Author(s) -
Barbareschi Mattia,
Pelosio Paola,
Caffo Orazio,
Buttitta Fiamma,
Pellegrini Silvia,
Barbazza Renzo,
Dalla Palma Paolo,
Bevilacqua Generoso,
Marchetti Antonio
Publication year - 1997
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19970422)74:2<171::aid-ijc5>3.0.co;2-w
Subject(s) - cyclin d1 , cyclin d , cancer research , biology , gene duplication , cyclin b , cyclin a2 , cyclin , retinoblastoma protein , immunohistochemistry , cyclin a , microbiology and biotechnology , cell cycle , gene , genetics , immunology
Cyclin D1 is a major positive regulator of the G 1 restriction point promoting inactivation of the retinoblastoma protein (RB). The cyclin D1 gene is rearranged, amplified and/or over‐expressed in several human neoplasms. In the present series of 64 human breast carcinomas, cyclin D1 amplification (4‐ to 8‐fold) was seen in 24% of cases, and cyclin‐D1 immunohistochemical over‐expression was seen in 50% of cases. Amplification and over‐expression were statistically associated; however, divergent result were seen in 30% of cases. Some of these discrepancies may reflect the fact that cyclin‐D1 expression may be due to mechanisms other than gene amplification. Cyclin‐D1 over‐expression, but not cyclin‐D1 amplification, was associated with positive oestrogen‐receptor immunoreactivity. Cyclin‐D1 amplification was associated with high RB expression, and 4 cases (7%) with absent RB immunoreactivity showed no cyclin‐D1 amplification nor expression. Our data support the hypothesis that cyclin‐D1 amplification may be associated with enhanced gene transcription and with high RB expression, that high ER expression may cooperate in maintaining high levels of cyclin‐D1 protein, and that loss of RB function, as assessed by the lack of RB immunoreactivity, may be related to normal cyclin‐D1 gene copy number and low cyclin‐D1 expression. Int. J. Cancer 74:171‐174, 1997. © 1997 Wiley‐Liss, Inc.